Presently, among other things, micromirrors or micromirror arrays are used for the optical deflection of light beams, as performed in projectors or in scanners, for example. Today, the use of such micromirrors is also being considered for head-up displays in motor vehicles.
As a rule, micromirrors have two swivel axes that are perpendicular to each other. In two-axis micromirrors, the mirror is usually suspended cardanically on a movable frame. For the purpose of deflecting light beams in two mutually independent spatial directions (2D=two-dimensional) or for the purpose of changing the direction of deflection of the light beams in two independent spatial planes, it must be possible to drive the control shafts of the two rotational axes of the mirror independently of each other. The rotations of the mirrors around the two axes must also be detected separately from one another as part of a regulation of the light deflection. Moreover, the two independent rotation mechanisms may also have different or opposite requirements with regard to their environmental conditions (i.e., air pressure/vacuum). Such systems for light deflection are therefore complex, expensive, and susceptible to faults.
In particular for designing and manufacturing a scanner, instead of such a complex 2D system, for example, it would be possible to combine two separate 1D scanners (that is, mirrors that rotate around only one single axis), which would allow for the two individual scanners to be optimized separately and independently. However, this would have the disadvantage that both 1D scanners would have to be adjusted to one another in a painstaking manner. Thus, in such an arrangement, no reduction of the size or the complexity of the overall system is to be expected.
The optics of imaging systems presents an additional challenge. These frequently use three color light sources, e.g., red, green, and blue laser diodes (=R-LD, G-LD, B-LD). The light radiation of these laser diodes must be brought into coincidence in order to be focused jointly onto a projection surface.